1. Field of the Invention
The present invention relates to a time-of-flight mass spectrometer (TOF-MS) array instrument. Each spectrometer of the array instrument includes (1) a gridless, focusing ionization extraction device allowing for the use of very high extraction energies in a maintenance-free design, and (2) a low-noise, center-hole microchannel plate detector assembly that significantly reduces the noise (or xe2x80x9cringingxe2x80x9d) inherent in the coaxial design and (3) a fiberglass-clad flexible ciruitboard reflector that is both simple to manufacture and extremely rugged in design. The circuitboard reflector is the enabling technology for simplified construction of the arrayed TOF mass analyzers compared to conventional reflectron TOF-MS designs.
2. Description of the Related Art
Miniature time-of-flight mass spectrometers (TOF-MS) have the potential to be used in numerous field-portable and remote sampling applications due to their inherent simplicity and potential for ruggedization. Conventional wisdom, however, holds that a compact TOF-MS would not have sufficient drift length to achieve high performance, as measured by good resolving power or the capability to detect and identify product ions.
Without the benefit of an extended drift region (and thereby long flight times), good resolution can only be achieved in a compact TOF-MS if the ion peaks are quite narrow. All aspects of the miniature analyzer and ionization processes that affect ion peak widths must therefore be optimized for minimum peak broadening to improve the overall performance of the field portable miniature TOF-MS.
Commercially available short-pulse lasers and fast transient digitizers enable the creation and measurement of very narrow ion signals, but the ion source region, reflector performance, and detector response will each contribute to the final peak width as well. To this end, components need to be developed for the miniature TOF-MS that improve its overall performance.
Further, due to its high throughput capabilities, TOF mass spectrometry is becoming a major analytical technology used for automated analysis. However, only large, single analyzer TOF-MSs are being used to xe2x80x9creadxe2x80x9d a sample substrate, typically a silicon chip or membrane with an array of hundreds or even thousands of sample sites. These commercially available and large TOF-MSs are both expensive and slow, allowing for only a single mass analyzer, and therefore single sample substrate per TOF-MS.
A need therefore exists for a TOF-MS instrument that allows for the bundling of a plurality of mass analyzers, e.g., a plurality of TOF-MSs, into a single array working in parallel fashion to greatly enhance the throughput in the array TOF-MS by multiplexing the data collection process. Construction of such an arrayed TOF-MS is greatly facilitated by utilizing the aforementioned components discussed above.
The present invention provides a time-of-flight mass spectrometer (TOF-MS) array instrument. Each TOF-MS of the array instrument includes (1) a gridless, focusing ionization extraction device allowing for the use of very high extraction energies in a maintenance-free design, (2) a flexible circuit-board reflector using rolled flexible circuit-board material encased in a fiberglass shell, and (3) a low-noise, center-hole microchannel plate detector assembly that significantly reduces the noise (or xe2x80x9cringingxe2x80x9d) inherent in the coaxial design. The components described herein improve the overall performance of the TOF-MS. These components have been developed with special attention paid to ruggedness and ease of construction for operation of the TOF-MS.
The TOF-MS array instrument allows for the bundling of a plurality of mass analyzers, e.g., a plurality of TOF-MSs, into a single array working in parallel fashion to greatly enhance the throughput of the TOF mass spectrometers by multiplexing the data collection process. A possible embodiment of the TOF-MS array instrument incorporates 16 TOF-MS units that are arranged in mirror-image clusters of eight units.